Door and window sensors using ambient infrared

ABSTRACT

A sensor assembly for detecting open or closed state in windows and doors includes a passive infrared sensor configured to produce a change in an electrical signal based on a change in infrared radiation incident on the passive infrared sensor. A lens is operatively connected to the passive infrared sensor. At least a portion of the lens is configured to be mounted in an interface between a frame and a door or window mounted to open and close within the frame. The lens is configured to guide ambient infrared radiation to the passive infrared sensor at a first level when the door or window is closed and at a second level when the door or window is open or ajar.

RELATED APPLICATIONS

This application is a U.S. National Stage Application ofPCT/US2015/015344 filed Feb. 11, 2015, which claims the benefit of andpriority to U.S. Provisional Patent Application No. 61/949,443 filedMar. 7, 2014, the contents of which are incorporated herein by referencein their entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present disclosure relates to sensors, and more particularly tosensors for detecting whether doors, windows, and the like are closed orajar, for example in security systems.

2. Description of Related Art

Many traditional sensors for detecting intrusion through a door orwindow, for example, rely on magnetic sensors. One magnetic sensorcomponent is attached to the door or window, for example, and acorresponding sensor component is attached to the respective door orwindow frame. When the two components are close together, as when thedoor or window is closed, the magnetic field of one sensor component canbe registered by the other, indicating the door or window is secure.When the door or window is opened, the magnetic field of the one sensorcomponent is no longer registered by the other, indicating a possibleintrusion.

Such conventional methods and systems have generally been consideredsatisfactory for their intended purpose. However, there is still a needin the art for improved sensors for detecting whether doors, windows,and the like are secure. The present disclosure provides a solution forthis need.

SUMMARY OF THE INVENTION

A sensor assembly for detecting open or closed state in windows anddoors includes a passive infrared sensor configured to produce a changein an electrical signal based on a change in infrared radiation incidenton the passive infrared sensor. A lens is operatively connected to thepassive infrared sensor. At least a portion of the lens is configured tobe mounted in an interface between a frame and a door or window mountedto open and close within the frame. The lens is configured to guideambient infrared radiation to the passive infrared sensor at a firstlevel when the door or window is closed and at a second level when thedoor or window is open or ajar.

In certain embodiments, the lens is configured to receive ambientinfrared radiation incident thereon from a first direction, and todirect infrared radiation onto the passive infrared sensor in a seconddirection different from the first direction. For example, the first andsecond directions can be about 90° apart.

It is contemplated that the lens can include a first portion housing thepassive infrared sensor and includes an ambient window configured toface an ambient environment. The lens can also that includes a secondportion angled relative to the first portion, wherein the second portionis configured to be mounted in the interface between a frame and a dooror window mounted to open and close within the frame. The first andsecond portions of the lens can be operatively connected to one anotherto direct ambient infrared radiation incident on the ambient window ofthe first portion, into the second portion, and through the secondportion to the passive infrared sensor in the first portion. The secondportion of the lens can include an interface window configured to be inthe interface between a frame and a door or window, wherein theinterface window is configured to alter how much infrared radiation isincident on the passive infrared sensor depending on whether the door orwindow is closed. It is contemplated that at least the second portion ofthe lens can have a thickness less than about 2 mm.

The lens can include an adhesive surface configured for mounting thelens with at least a portion of the lens in the interface between aframe and a door or window mounted to open and close within the frame.The lens can include an acrylic material, or any other suitablematerial. The passive infrared sensor can be a first passive infraredsensor, and a second infrared sensor can be operatively connected to thelens, wherein the second infrared sensor is oriented in a direction toreceive a level of ambient infrared radiation independent of whether thedoor or window is closed for adjustment of the first passive infraredsensor to account for changes in ambient infrared levels. It is alsocontemplated that a capacitive sensor can be operatively connected tothe lens to detect a change in capacitance based on whether the door orwindow is closed to provide an additional modality of detection.

In another aspect, a security sensor assembly for detecting open orclosed state in windows and doors includes a single piece passivenon-magnetic sensor configured to produce a change in an electricalsignal based on open or closed state of a door or window. The singlepiece passive non-magnetic sensor can be configured to be unaffected bylong term changes in geometry of the door or window of greater than oneinch in magnitude. The single piece passive non-magnetic sensor caninclude an adhesive surface configured for mounting to at least one of adoor frame, a door, a window frame, a window, or the like.

A method of detecting the state of a door or window includes receivingambient infrared radiation with a passive infrared sensor at a firstlevel when a door or window is in a closed state. The method alsoincludes receiving ambient infrared radiation with the passive infraredsensor at a second level different from the first level when the door orwindow is open or ajar.

In accordance with certain embodiments, receiving ambient infraredradiation with a passive infrared sensor at a first level when a door orwindow is in a closed state includes guiding a first level of ambientinfrared radiation through a lens to the passive infrared sensor.Receiving ambient infrared radiation with the passive infrared sensor ata second level different from the first level when the door or window isopen or ajar can include guiding a second level of ambient infraredradiation through the lens to the passive infrared sensor.

At least a portion of the lens can be positioned in an interface betweena frame and the door or window when the door or window is closed.Guiding a first level of ambient infrared radiation through a lens tothe passive infrared sensor can include allowing a first level of lossof ambient infrared radiation from the lens due to the door or windowbeing closed, and guiding a second level of ambient infrared radiationthrough a lens to the passive infrared sensor can include allowing asecond level of loss of ambient infrared radiation from the lens due tothe door or window being open or ajar. The lens can receive ambientinfrared radiation incident thereon from a first direction, and candirect infrared radiation onto the passive infrared sensor in a seconddirection different from the first direction.

In another aspect, the passive infrared sensor is a first passiveinfrared sensor and the method can include receiving a level of ambientradiation with a second passive infrared sensor oriented in a directionto receive a level of ambient radiation independent of whether the dooror window is closed. The method can include adjusting the first passiveinfrared sensor to account for changes in ambient infrared levels. It isalso contemplated that the method can include detecting whether the dooror window is closed using a capacitive sensor to provide an additionalmodality of detection.

These and other features of the systems and methods of the subjectdisclosure will become more readily apparent to those skilled in the artfrom the following detailed description of the preferred embodimentstaken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

So that those skilled in the art to which the subject disclosureappertains will readily understand how to make and use the devices andmethods of the subject disclosure without undue experimentation,preferred embodiments thereof will be described in detail herein belowwith reference to certain figures, wherein:

FIG. 1 is a perspective view of an exemplary embodiment of a sensorassembly constructed in accordance with the present disclosure, showingthe lens from within;

FIG. 2 is a perspective view of the sensor assembly of FIG. 1, showingthe lens from the opposite side of that shown in FIG. 1, andschematically indicating the pathways of ambient radiation into thepassive infrared sensor;

FIG. 3 is a schematic perspective view of a door frame with the sensorassembly of FIG. 1 mounted thereto, showing the orientation of the twoportions of the lens relative to the door and door frame;

FIG. 4 is a cross-sectional plan view of the sensor assembly of FIG. 1,showing the lens mounted to the door frame with a portion of the lensbetween the door and the doorframe with the door closed; and

FIG. 5 is a cross-sectional plan view of the sensor assembly of FIG. 1,showing the lens mounted to the door frame with the door ajar.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made to the drawings wherein like referencenumerals identify similar structural features or aspects of the subjectdisclosure. For purposes of explanation and illustration, and notlimitation, a partial view of an exemplary embodiment of a sensorassembly in accordance with the disclosure is shown in FIG. 1 and isdesignated generally by reference character 100. Other embodiments ofsensor assemblies in accordance with the disclosure, or aspects thereof,are provided in FIGS. 2-5, as will be described. The systems and methodsdescribed herein can be used for detection of whether doors, windows, orthe like, are secure.

Sensor assembly 100 shown in FIG. 1 is configured for detecting open orclosed state in windows, doors, and the like. Sensor assembly 100includes a passive infrared sensor 102, identified in FIG. 2, which isconfigured to produce a change in an electrical signal based on a changein infrared radiation incident on the passive infrared sensor 102. Alens 104 is operatively connected to the passive infrared sensor 102.Lens 104 includes two portions, namely a first lens portion 106 housingpassive infrared sensor 102, and a second lens portion 108 that isconfigured to be mounted in an interface 140 (identified in FIG. 4)between a frame and a door or window mounted to open and close withinthe frame, as will be further described below. Lens 104 defines anL-shaped cross-section as shown in FIGS. 1 and 2, wherein second lensportion 108 is angled 90° relative to the first lens portion 106. Lens104 can include an adhesive surface 128 for mounting lens 104 to a door,window, or frame for a door or window. For example, the entire innersurface of first and second lens portions 106 and 108 can be coveredwith an adhesive, as indicated in FIG. 1, or only a portion of thatinner surface can include the adhesive. Any other suitable method foraffixing lens 104 can also be used without departing from the scope ofthis disclosure.

With reference now to FIG. 2, lens 104 is configured to guide ambientinfrared radiation to the passive infrared sensor 102 at a first levelwhen the door or window is closed and at a second level when the door orwindow is open or ajar. Lens portion 106 houses the passive infraredsensor 102 and includes an ambient window 112 configured to face anambient environment. Lens 104 is configured to receive ambient infraredradiation incident thereon from a first direction, and to directinfrared radiation onto the passive infrared sensor 102 in a seconddirection different from the first direction. The first and second lensportions 106 and 108 are operatively connected to one another to directambient infrared radiation, represented by arrow 114 in FIG. 2, incidenton the ambient window 112, into the second lens portion 108 as indicatedby arrow 116, through the second lens portion 108 as indicated by arrow118, back into the first lens portion 106 as indicated by arrow 120, andto the passive infrared sensor 102 in the first lens portion 106. Inthis example, the direction, e.g., arrow 114, at which ambient radiationis received at lens 104 is different by 90° from the direction, e.g.,arrow 120, at which the radiation is received at passive infrared sensor102. However those skilled in the art will readily appreciate that anyother suitable directions or angles can be used without departing fromthe scope of this disclosure. A shield or pattern inscribed in lens 104between window 112 and the upper half of lens portion 106 can blockradiation from passing directly from window 112 to sensor 102.

Lens 104 includes an acrylic material, and the optical connectionbetween first and second lens portions 106 and 108 can be by means ofboth being formed integrally of a single acrylic part. It is alsocontemplated that the first and second lens portions 106 and 108 can beformed separately of acrylic and then joined by any suitable means thatallows optical communication of ambient radiation from one lens portionto the other. Any other suitable materials can be used for lens 104.Lens 104 serves as a wave guide to convey ambient infrared radiation topassive infrared sensor 102. It is to be understood that sensor assembly100 and its components are not necessarily drawn to scale in FIGS. 1-5.The first and second lens portions 106 and 108 are dimensioned to beeffective waveguides, and second portion 108 is dimensioned to occupythe space between a door or window and its frame without interferingwith operation of the door or window. For example, it is contemplatedthat the second lens portion 108 can have a thickness less than about 2mm.

The first lens portion 106 includes a shielding layer 122 that blocksambient radiation from reaching passive infrared sensor 102 directlywithout passing through second lens portion 108. The second lens portion108 includes an interface window 124 configured to be in and face intothe interface 140 (identified in FIG. 4) between a frame and a door orwindow, e.g., to face in the direction from the door frame to the doorwhen the door is closed. Interface window 124 is configured to alter howmuch infrared radiation is incident on the passive infrared sensor 102depending on whether the door or window is closed. Arrow 126 in FIG. 2indicates radiation losses or gains that change depending on the open orclosed state of the door or window, which change corresponds to a changein the infrared radiation input at passive infrared sensor 102 dependenton the open or closed state of the door or window.

Lens 104 can be used to amplify sensitivity to infrared radiationreceived at passive infrared sensor 102 by focusing infrared radiationonto a smaller area of the surface to be detected. For example interfacewindow 124 and/or ambient window 112 can include a convex lens,diffraction grating, Fresnel lens, or the like to provide the focusing.This can be accomplished, for example, by scoring the surface ofinterface window 124 and/or ambient window 112 to form a Fresnel lens ordiffraction grating.

As shown in FIG. 2, passive infrared sensor 102 is housed in a sensorunit 130 and is oriented to receive infrared radiation from thedirection of second lens portion 108. A second infrared sensor 132 canoptionally be housed in sensor unit 130 or in any other suitablelocation, e.g. facing outward through shielding layer 122, to have aview of the ambient environment. This makes the second passive infraredsensor 132 operative to receive a level of ambient infrared radiationthat is unaffected by or independent of whether the door or window isclosed. This information can be used for adjustment of the first passiveinfrared sensor 102, or the signal therefrom, to account for changes inambient infrared levels that should not trigger an alarm, for example.It is also contemplated that an optional capacitive sensor 134 can beoperatively connected to lens 104 and sensor unit 130 to detect a changein capacitance based on whether the door or window is closed to providean additional modality of detection of door or window state.

Referring now to FIG. 3, sensor assembly 100 can be used as a securitysensor for detecting open or closed state in windows and doors, using asingle piece passive non-magnetic sensor configured to produce a changein an electrical signal based on open or closed state of a door orwindow as already described. This is in contrast to magnetic securitysystems that use two separate pieces, one affixed to a door or window,and the other affixed to the frame of the door or window. Since sensorassembly 100 only uses a single piece passive non-magnetic sensor, it isconfigured to be unaffected by long term changes in geometry of the dooror window. For example, sensor assembly 100 can tolerate changes ingeometry over time of greater than one inch in magnitude, whereastypical two-piece magnetic sensors can be rendered inoperative by suchchanges over time.

As shown in FIG. 3, the single piece passive non-magnetic sensorassembly 100 can be mounted to a door frame with the ambient window 116faced outward toward ambient conditions, e.g., toward the exteriorconditions or interior conditions of a room, and with interface window124 facing inward into the interface 140 (identified in FIG. 4) betweendoor 136 and door frame 138 when door 136 is in the closed position.Another exemplary position for a sensor assembly 100′ is shown in dashedlines in FIG. 3, namely on door 136, with ambient window 116′ facingtoward ambient and with interface window 124′ arranged to face into theinterface 140 (identified in FIG. 4) between the door 136 and frame 138when the door 136 is in the closed position. As shown in FIG. 4, secondlens portion 108 is positioned in an interface 140 between a frame 138and the door 136 the door is closed. Those skilled in the art willreadily appreciate that sensor assemblies in accordance with thisdisclosure can affixed to a door, a door frame, a window, a windowframe, or any other suitable place.

Referring now to FIGS. 4 and 5, a method of detecting the state of adoor or window is described. The method includes receiving ambientinfrared radiation with a passive infrared sensor 102 at a first levelwhen a door 136 is in a closed state as shown in FIG. 4. The method alsoincludes receiving ambient infrared radiation with the passive infraredsensor 102 at a second level different from the first level when thedoor 136 is ajar or open, as shown in FIG. 3. This change in ambientinfrared radiation reaching passive infrared sensor 102 is due todifferent levels in losses or gains in infrared radiation guided topassive infrared sensor 102 when door 136 is open, as indicated by arrow126 in FIGS. 2 and 5, which are different from the levels of loss orgain when door 136 is closed as shown in FIG. 4.

Thus when a door or window is in a closed state, sensor assembly 100guides a first level of ambient infrared radiation through lens 104 tothe passive infrared sensor 102. When the door or window is ajar oropen, sensor assembly 100 guides a second level of ambient infraredradiation through lens 104 to the passive infrared sensor 102. Passiveinfrared sensor 102 can therefore impart a change on an electricalsignal based on whether the door is closed or not, and the change insignal can be used to monitor the door, e.g., for security or alarmpurposes.

The method can include receiving a level of ambient radiation with asecond passive infrared sensor 132 oriented in a direction to receive alevel of ambient radiation independent of and unaffected by whether thedoor or window is closed, e.g., passive infrared sensor 132 sees throughan aperture in shielding layer 122 and is oriented to directly detectambient radiation from the direction indicated by arrow 114 in FIG. 2.The method can therefore include adjusting the first passive infraredsensor 102, or the signal therefrom, to account for changes in ambientinfrared levels. For example, if there is a certain change in theambient infrared environment, but the door 136 has not changed frombeing closed, an alarm will not sound if the reading from the secondpassive infrared sensor 132 is used as described above.

Sensor unit 130, shown in FIG. 2, is operatively connected to passiveinfrared sensor 102 and optional second passive infrared and capacitivesensors 132 and 134. Those skilled in the art will readily appreciatethat sensor unit 130 can include any suitable components to support thesensor function described above. For example, sensor unit 130 caninclude a power source for powering the sensors, control logic fordetermining the state of the door or window, and an antenna forwirelessly transmitting data regarding the state of the door or windowto a central security system.

In one example, a 1 μA passive infrared sensor can be used, e.g., aspassive infrared sensor 102. With or without the second passive infraredsensor 132, an initial calibration can be used to initialize thesensitivity. An advantage of using passive infrared sensors is that noexcitation, such as from a near infrared light emitting diode (NIR LED),is required. However, it is contemplated that active infraredfunctionality could optionally be added if suitable for certainapplications. Only one device needs to be affixed, e.g., to the door orframe, to be able to sense the state of a door or window, rather thantwo devices as in active infrared or magnetic sensor systems. Thoseskilled in the art will readily appreciate that motion detection can beoptionally added to sensors in accordance with this disclosure, and thatsensors as described above can potentially be mounted where traditionalsensors cannot, giving potential benefits of flexibility in installationcompared to traditional systems.

While described above in the exemplary context of sensing the open,closed, and/or ajar state of doors that hinge open and closed, any othersuitable applications including windows and any type of door or openingis contemplated. Moreover, those skilled in the art will readilyappreciate that systems and methods as described herein can readily beapplied to doors, windows, and the like that slide, roll, or move in anyother suitable manner without departing from the scope of thisdisclosure. Besides doors and windows, the methods and apparatusdescribed herein can be used in any other suitable moving interface. Forexample, a sensor assembly as described above can be mounted in theinterface between any two suitable surfaces that move relative to oneanother, e.g., moving between a first and second position, to detect themovement.

Additionally, while described in the exemplary context of detectingwhether a door closed versus open or ajar, those skilled in the art willreadily appreciate that the systems and methods described herein canalso be used to detect movement of the door or window, for example ifthe door or window starts ajar and then moves. It is also contemplatedthat the systems and methods described herein can be used to detect if adoor or window is completely open because of the amplitude differencethat can be detected due to the lack of interaction between the door orwindow edge and the sensor.

The methods and systems of the present disclosure, as described aboveand shown in the drawings, provide for sensors for detecting whetherwindows, doors, or the like, are closed. While the apparatus and methodsof the subject disclosure have been shown and described with referenceto preferred embodiments, those skilled in the art will readilyappreciate that changes and/or modifications may be made thereto withoutdeparting from the spirit and scope of the subject disclosure.

What is claimed is:
 1. A sensor assembly for detecting open or closedstate in windows and doors comprising: a passive infrared sensorconfigured to produce a change in an electrical signal based on a changein infrared radiation incident on the passive infrared sensor; and alens operatively connected to the passive infrared sensor, wherein atleast a portion of the lens is configured to be mounted in an interfacebetween a frame and a door or window mounted to open and close withinthe frame, and wherein at least a portion of the lens is a waveguidethat is configured to guide ambient infrared radiation to the passiveinfrared sensor at a first level when the door or window is closed andat a second level when the door or window is ajar, wherein the lensincludes: a first portion housing the passive infrared sensor andincluding an ambient window configured to face an ambient environment;and a second portion angled relative to the first portion, wherein thesecond portion is configured to be mounted in the interface between aframe and a door or window mounted to open and close within the frame,wherein the first and second portions of the lens are operativelyconnected to one another to direct ambient infrared radiation incidenton the ambient window of the first portion, into the second portion,through the second portion to the passive infrared sensor in the firstportion.
 2. The sensor assembly of claim 1, wherein the lens isconfigured to receive ambient infrared radiation incident thereon from afirst direction, and to direct infrared radiation onto the passiveinfrared sensor in a second direction different from the firstdirection.
 3. The sensor assembly of claim 2, wherein the first andsecond directions are about 90° apart.
 4. The sensor assembly of claim1, wherein the second portion of the lens includes an interface windowconfigured to face into the interface between a frame and a door orwindow, wherein the interface window is configured to alter how muchinfrared radiation is incident on the passive infrared sensor dependingon whether the door or window is ajar.
 5. The sensor assembly of claim1, wherein at least the second portion of the lens has a thickness lessthan about 2 mm.
 6. The sensor assembly of claim 1, wherein the lensincludes an adhesive surface configured for mounting the lens with atleast a portion of the lens in the interface between a frame and a dooror window mounted to open and close within the frame.
 7. The sensorassembly of claim 1, wherein the lens includes an acrylic material. 8.The sensor assembly of claim 1, further comprising a capacitive sensoroperatively connected to the lens to detect a change in capacitancebased on whether the door or window is ajar to provide an additionalmodality of detection.
 9. The sensor assembly of claim 1, wherein thepassive infrared sensor is a first passive infrared sensor, and furthercomprising a second infrared sensor operatively connected to the lens,wherein the second infrared sensor is oriented in a direction to receivea level of ambient infrared radiation independent of whether the door orwindow is ajar for adjustment of the first passive infrared sensor toaccount for changes in ambient infrared levels.
 10. A sensor assemblyfor detecting state of an interface between two surfaces: a passiveinfrared sensor configured to produce a change in an electrical signalbased on a change in infrared radiation incident on the passive infraredsensor; and a lens operatively connected to the passive infrared sensor,wherein at least a portion of the lens is configured to be mounted in aninterface between a first surface and a second surface movable relativeto the first surface, and wherein the lens is a waveguide that isconfigured to guide ambient infrared radiation to the passive infraredsensor at a first level when the first surface is in a first positionrelative to the second surface and at a second level when the firstsurface is in a second position relative to the second surface, whereinthe lens includes: a first portion housing the passive infrared sensorand including an ambient window configured to face an ambientenvironment; and a second portion angled relative to the first portion,wherein the second portion is configured to be mounted in the interfacebetween a frame and a door or window mounted to open and close withinthe frame, wherein the first and second portions of the lens areoperatively connected to one another to direct ambient infraredradiation incident on the ambient window of the first portion, into thesecond portion, through the second portion to the passive infraredsensor in the first portion.